What do you mean by Regular geometry and Irregular or Distorted geometry?
Regular geometry: The molecules in which the central atom is surrounded only by similarly bonded electron pairs will have regular geometries. The central atom should have no lone pair of electrons and should be bonded to all similar atoms. For example CH4, CCl4, BF3 etc.
Irregular or Distorted geometry: The molecules in which the central atom is surrounded by bond pairs, as well as lone pairs, will have irregular geometries. The central atom may be bonded to similar atoms but should have different bond lengths.
For example, CHCl3, CHBr3, PF5.
Read more: Which of the following compounds contains a double bond?